Toe iron for safety ski bindings

ABSTRACT

A soleholder member constituting a coupling link of a four-bar linkage, which comprises levers that are pivoted to a baseplate which is secured to the ski. The four-bar linkage is modified in that the levers consist of toggle joints, which have toggle arms that are pivoted to the baseplate and the arms in the normal position of the toe iron diverge and engage stationary stops, whereas the other toggle arms of the toggle joints in the position of the toe iron converge from the hinges. A spring urges the soleholder member to its normal position.

United States Patent- Schriewer 51 Apr. 18, 1972 54] TOE IRON FOR SAFETYSKI BINDINGS FOREIGN PATENTS 0R APPLICATIONS [72] Inventor; ErnsbmchardSch-kw", i p 488,469 12/ 1967 Switzerland ..230/1 1.35 T

tenkuchen Germany 1 Primary Examiner -Benjamin Hersh [7 3] Assignee:Hannes Marker, Garmisch-Partenkirchen, Assistant Examineri-Rob'ert R.Song Germany AttorneyFleit, Gipple & Jacobson [22] Filed: May 26, 1970[57] ABSTRACT [21] Appl' 40546 A soleholder memberconstituting aCoupling link of a fourbar linkage, which comprises levers that arepivoted to a 30 Foreign Application priority t baseplate which issecured to the ski. The four-bar linkage is modified in that the leversconsist of toggle joints, which have June 23, Germany ..P I toggle armsthat are pivoted to the baseplate and the arms in the normal position ofthe toe iron diverge and engage sta- [52] U.S.Cl.... ..280/1L35T tionarystops, whereas the other toggle arms of the toggle [51] Int. Cl /0joints in the position of the toe iron converge from the hinges. [58]Field of Search ..280/1 l.35 T A spring urges the soleholder member toits normal position. [56] References Cited 7 7 f UNITED STATES PATENTS3,125,349 3/1964 Schweizer ..280/ll.35T

l6 30 in PATENTEmPmmzv 3.656;!74

sum 10F 2- a "WW ERNST-R|CNARD SCflRtEWER Mot, 4/ 1, ywlm v I Btu-my thetoe iron is in its normal position, the soleholder member locked inposition relative to the baseplate by a ball detent device. The pressureby which the detent device is loaded can be varied to enable a settingof different forces required for a release.

This known toe iron has various disadvantages. The most essentialdisadvantage resides in that the soleholder member is locked relative tothe baseplate by a detent device so that the toe iron is highlysusceptible to shock. This results in unnecessary release actions andfalls, which lead to atypical skiing injuries so that the skier istempted to select an excessively hard setting for the toe iron. Thissetting may be result in a failure of the toe iron to release the bootin a critical instant so that the skier may suffer typical skiinginjuries, which ought to have been avoided by the use of the safetybinding.

It is an object of the present invention so to improve and design a toeiron for safety ski bindings of the kind previously described that thetoe iron is free of the disadvantages of the known toe iron.

In a toe iron for safety ski bindings, which toe iron comprises asoleholder member which constitutes a coupling link of a four-barlinkage, which comprises levers that are pivoted to a baseplate which issecured to the ski, this object is accomplished according to theinvention in that the four-bar linkage is modified in that the leversconsist of toggles, which have links that are pivoted to the baseplateand said links in the normal position of the toe iron diverge and engagestationary stops, whereas the other links of said toggles in saidposition of the toe iron converge from the hinges, and a spring urgesthe soleholder member to its normal position. This design eliminates theundesired susceptibility to shock. The toggles are designed so that thesoleholder member is moved before the safety release of the toe ironalong an are which is centered at least approximately on the imaginaryaxis of rotation of the skiing boot. In this way, a pivotal movement ofthe skiing boot does not result in a component of motion of said boottoward the tip of the ski under the action of the force which acts onthe heel and forces the boot against the toe iron.

In a special embodiment of the invention, the spring may act on thesoleholder member by two two-armed levers, which have fixed fulcrums andare pivotally movable in a horizontal direction. In such arrangement ithas proved desirable to provide said two levers so as to form a gripperhaving jaw arms, which embrace a coupling element carried by thesoleholder member whereas those arms of the levers which are opposite tosaid jaw arms are connected by a tension spring, which pulls the twoarms against a stationary stop. The force required for a release can bevaried in a simple manner if each lever arm is adapted to have thespring connected to it at least at two points. The selection of effortarms of different lengths in conjunction with a given spring force thenenables a selection of the torque which is desired in each case.

Those toggle links which are pivoted to the baseplate are suitably underthe influence of a weak return spring. This design will result in anexact return movement of the toggles after a safety release of the toeiron because the bearing friction will be overcome. In a development ofthis concept of the invention it has proved desirable to provide asingle return spring for both toggle links which are pivoted to thebaseplate and to use as a return spring an expanding spring having twolegs acting on respective toggle links.

An embodiment of the invention will now be described more fully withreference to the accompanying drawing, in which FIG. Us a centrallongitudinal sectional view showing a toe II'OII,

FIG. 2 is a sectional view taken on line lI-II of FIG. 1 and showing thetoe iron,

FIG. 3 is a sectional view which is similar to FIG. 2 but shows the toeiron immediately before a safety release and FIG. 4 is a sectional viewsimilar to FIG. 2 and shows the toe iron in an open position.

The toe iron for ski bindings which is shown on the drawings comprises abaseplate l, which is adapted to be connected to a ski, e.g., by meansof screws. For this purpose, the baseplate has two screw holes. Twotoggles 3, 4 are arranged with mirror symmetry and are pivoted to thebaseplate by respective pivot pins 5 and 6. The two toggles form partsof a modified four-bar linkage, which has a coupling link 7 in the formof a soleholder member. The coupling link is pivotally connected at 8and 9 to the toggles. The arrangement of the toggles is such that in thenormal position of the toe iron the toggle links 10, 11 pivoted to thebaseplate diverge and engage stops 12 and 13, respectively, and theother toggle links l4, l5 converge from the hinges 16, 17, where theyare connected to the toggle links 10, 11. The toggle links l0, 11 aresheet metal stampings, which are bent in U-shape, whereas the togglelinks 14, 15 are plain sheet metal stampings. The stops 12, 13 consistof parts of a cover cap 18, which is held on the baseplate l by lateralguides, not shown, and a screw 19 (see FIG. 1).

The cover cap 18 carries a vertical pivot pin 21, on which two two-armedlevers 22, 23 are mounted. These levers cooperate like a gripper. Theirjaw arms 24, 25 embrace a coupling element 26, which consists of avertical pin that is provided in the soleholder member 7. A prestressedtension spring 29 connects the other arms 27, 28 of the levers 22, 23and pulls the two arms against a stationary stop 30, which is formed bya raised portion of the baseplate 1. The lever arms 27, 28 are providedin their outer longitudinal .side, for instance, with four recesses 31,as shown, for receiving the hooklike end portions of the tension spring29.

The raised portion 30 of the baseplate l constitutes a bracket, whichdefines with the baseplate a space that accommodates an expanding spring33. The latter is held on a pin 32, which is mounted inthe baseplate andits raised portion. The legs 34, 35 of the expanding spring 33 act onthe links l0, 11 of the toggles 3, 4. The expanding spring is relativelyweak and serves only as a return spring for the rocker lever to overcomethe bearing friction thereof.

The sole-engaging element 36 is held on the soleholder member 7 by meansof a screw 37, which extends through a slot 38 formed in thesole-engaging element so that the latter can be adjusted to skiing bootsoles differing in thickness.

FIGS. 1 and 2 show the toe iron in its normal position. The spring 29 ishooked into the desired recesses 31 in the lever arms 27, 28 so that thetoe iron is set to the desired force required for a release. If thesoleholder member 7 is subjected to a force which is transverse to thelongitudinal direction of the toe iron and is directed, e.g., upwardlyin FIGS. 2 to 4 of the drawing and said force exceeds the initial stressof the spring 29, said force will impart to the four-bar linkage amovement against the force of the spring, as is shown in FIG. 3. Thecoupling element 26 of the soleholder member 7 causes thelever 22 tostress the tension spring 29 because the arm 28 of the lever 23 engagesthe stop 30. The toggle which is at the rear in the direction ofmovement, in the present case the toggle 4, performs a pivotal movementabout the pivot pin 6 which is fixed to the baseplate whereas the link10 of the toggle which is in front in the direction of movement, in thepresent case the toggle 3, engages the stop 12 so that only the link 14of the toggle performs a pivotal movement about the hinge 16. Thisaction imposes to the soleholder member 7 a movement on an are which isat least approximately centered on the imaginary axis of rotation of theskiing boot on the ski. Upon a decrease of the force acting on thesoleholder member, the spring 29 returns the four-bar linkage to itsnormal position shown in FIG. 2.

If a force which exceeds the desired force required for a release actson the soleholder member not merely as a shock,

the four-bar linkage will initially move again as previously movement ofthe soleholder member so that the latter releases the toe portion of theskiing boot virtually suddenly. When the skiing boot has been released,the spring 29 automatically returns the soleholder member 32 to itsnormal position. In

this operation, the spring 32 ensures that the snapped-in toggle isreliably returned to its initial position.

The force required for a release can be changed only when the cover cap18 has been removed. The screw 19 must be loosened for this purpose. Ifthe manufacturer or seller of the toe iron sets the latter to apredetermined force required for a release and subsequently seals thescrew 19, e.g., with lead, such seal will indicate that the forcerequired for a release has not been changed thereafter.

What is claimed is:

l. A toe iron for safety ski bindings comprising a baseplate, pivotmeans secured to said baseplate, the axesthereof being perpendicular tosaid baseplate, a four-bar linkage pivotally mounted on said pivotmeans, said four-bar linkage comprising a pair of toggle links, each ofsaid toggle links having forward and rearward toggle bars, said forwardtoggle bars being pivotally mounted on said pivot means, said rearwardtoggle bars being pivotally connected to a soleholder member, saidsoleholder member constituting a coupling link between said rearwardtoggle bars, said rearward toggle bars converging toward said pivotalconnection in the normal position of the toe iron while said forwardtoggle bars diverge from said pivot means and stop means connected tosaid baseplate for preventing said forward toggle bars from pivotingoutwardly from said normal position and spring means adapted to urgesaid soleholder member to its normal position.

2. A toe iron as claimed in claim 1 wherein said spring means comprisestwo two-arm levers which act on said soleholder member, said two-armedlevers having fixed fulcrurns and being pivotally movable in ahorizontal direction.

3. A toe iron as claimed in claim 2 wherein said levers have armsforming gripper means which embrace a coupling element carried by thesoleholder member, the opposite arms of the levers being connected by atension spring, said tension spring holding said opposite arms againststop means.

4. A toe iron as claimed in claim 3 wherein each lever arm can have thetension spring connected to it at at least two points.

5. A toe iron as claimed in claim 1 wherein said toggle bars which arepivoted to the baseplate are under the influence of a return spring.

6. A toe iron as claimed in claim 5 wherein said return spring comprisesan expanding spring having two-legs acting on the respective togglebars.

7. A toe iron comprising a baseplate having a raised portion, saidraised portion forming a bracket to accommodate expanding spring meansthereunder, pivot means secured to said baseplate, a four-bar linkagerotatably mounted to said pivot means, said four-bar linkage comprisinga pair of toggle bars pivotally mounted to said pivot means, rearwardmembers of said toggle bars being pivotally connected to a soleholdermember with the soleholder member forming a coupling link for the togglebars, forward members of said toggle bars being urged outwardly by saidexpanding spring means against stop means fixed to said baseplate, acover mounted to said baseplate, pivot means secured to said cover, apair of twoarmed levers pivotally mounted to said cover, each leverhaving one arm forming gripper means to engage a coupling elementcarried by the soleholder member with the arm opposite said gripper armbeing connected by a tension spring which pulls said other two armsagainst said raised portion.

1. A toe iron for safety ski bindings comprising a baseplate, pivotmeans secured to said baseplate, the axes thereof being perpendicular tosaid baseplate, a four-bar linkage pivotally mounted on said pivotmeans, said four-bar linkage comprising a pair of toggle links, each ofsaid toggle links having forward and rearward toggle bars, said forwardtoggle bars being pivotally mounted on said pivot means, said rearwardtoggle bars being pivotally connected to a soleholder member, saidsoleholder member constituting a coupling link between said rearwardtoggle bars, said rearward toggle bars converging toward said pivotalconnection in the normal position of the toe iron while said forwardtoggle bars diverge from said pivot means and stop means connected tosaid baseplate for preventing said forward toggle bars from pivotingoutwardly from said normal position and spring means adapted to urgesaid soleholder member to its normal position.
 2. A toe iron as claimedin claim 1 wherein said spring means comprises two two-arm levers whichact on said soleholder member, said two-armed levers having fixedfulcrums and being pivotally movable in a horizontal direction.
 3. A toeiron as claimed in claim 2 wherein said levers have arms forming grippermeans which embrace a coupling element carried by the solehOlder member,the opposite arms of the levers being connected by a tension spring,said tension spring holding said opposite arms against stop means.
 4. Atoe iron as claimed in claim 3 wherein each lever arm can have thetension spring connected to it at at least two points.
 5. A toe iron asclaimed in claim 1 wherein said toggle bars which are pivoted to thebaseplate are under the influence of a return spring.
 6. A toe iron asclaimed in claim 5 wherein said return spring comprises an expandingspring having two legs acting on the respective toggle bars.
 7. A toeiron comprising a baseplate having a raised portion, said raised portionforming a bracket to accommodate expanding spring means thereunder,pivot means secured to said baseplate, a four-bar linkage rotatablymounted to said pivot means, said four-bar linkage comprising a pair oftoggle bars pivotally mounted to said pivot means, rearward members ofsaid toggle bars being pivotally connected to a soleholder member withthe soleholder member forming a coupling link for the toggle bars,forward members of said toggle bars being urged outwardly by saidexpanding spring means against stop means fixed to said baseplate, acover mounted to said baseplate, pivot means secured to said cover, apair of two-armed levers pivotally mounted to said cover, each leverhaving one arm forming gripper means to engage a coupling elementcarried by the soleholder member with the arm opposite said gripper armbeing connected by a tension spring which pulls said other two armsagainst said raised portion.